DTMF Masking

Get the facts about DTMF Masking for secure data entry, as used in our CallGuard solution.

Why Keying in Card Details is Safer

Gone are the days when you can legitimately ask your customers to speak their details over the phone without there being some risk to their data. Whether it's someone in close proximity overhearing them relay the data, agents (perfect strangers) hearing and typing in the information, or the call recordings that store the conversations - it's a security risk.

But securing telephone payments is notoriously difficult from an IT and processes perspective. You have the 'human' discussion factor to contend with, unlike web or app payments where the customer isn't engaging in a dialogue. That's why more businesses are opting to use a DTMF Masking solution for enhanced telephone payment security.

So what is DTMF and how do you secure it? Read on to find out.

DTMF Masking

DTMF as a Voice Alternative

The alternative to asking your customers to speak their card details over the phone is to ask them to type this numeric information into their telephone keypad. This avoids the details being overheard by bystanders or the agent.

Sending sensitive data in this way has a clear security advantages.

Without any form of masking, card details can end up permanently stored in call recording systems, leaving them open to access.

About DTMF

DTMF stands for Dual Tone, Multi-Frequency, which is the tone that's given on each key press of a 'touchtone' telephone keypad.

When each key is pressed on your phone, it generates two frequencies. One tone is generated from a high-frequency range of tones and the other from a low frequency group.

This means a voice cannot imitate the tones.

DTMF Masking for PCI DSS Compliance

In 2009, Eckoh launched EckohPAY, a hosted IVR system that enabled customers to make payments over the phone using an automated system after speaking with an agent. The details were captured in Eckoh's PCI Level 1 compliant platform and authorised payment on behalf of the client.


But organisations started wanting a more customer friendly alternative which allows the agent to stay on the phone with the customer during the whole transaction process.


Two years later, Eckoh launched CallGuard which changes the sound of the DTMF tones to flat 'monotones' as they enter the organisation. Put simply, the tones made by your customer's telephone keypad are 'masked' and cannot be identified by their sound. Any conversation between your agents and the customer can continue uninterrupted. DTMF tones don't appear in your call recordings either.


In addition, as the information is tapped in, it populates fields on the agent's screen. The agent only sees asterisks and the last four digits of the card number as an identifier.

De-Scope Your Whole Contact Centre

If you want to remove all or part of your contact centre from scope, then CallGuard help you meet your PCI DSS requirements.

CallGuard secures any part of your contact centre including agents, call recordings, terminals, networks, telephony systems and processes. It is available as both hosted or on-premise implementations to suit your business needs.

Payments Don't Always Need an Agent

If you are a utilities, finance or subscriptions company and need to offer your customers a fast self-service method to take recurring payments, then EckohPAY may be the right option for your business.

EckohPAY secures all payments made over the phone using an automated system that gently takes your customers through each step of the payment process.

Like The Idea but Worried About the Integration?

If time and resources aren't on your side, you can get all the benefits of a DTMF Masking solution, without the worry of any IT integration costs. Our new Audio Tokenisation Solution is simple and quick to set-up, and de-scopes your entire contact centre solution